Foam stabilizer



Patented Feb. 24, 1925.

NATHANIEL T. EWER, OF SWAR'IHMORE, PENNSYLVANIA, ASSIGNOR TO AMERICANDYEWOOD COMPANY, OF NEW YORK, N. Y., A. CORPORATION OF PENNSYLVANIA.

FOAM STABILIZER.

No Drawing.

To all whom it may concern:

Be it known that I, NATHANIEL T. EWER, a citizen of the United States,residing at Swarthmore, in the county of Delaware, State ofPennsylvania, have invented certain new and useful Improvements in FoamStabilizers; and I do hereby declare the following to be a full, clear,and exact description of the invention, such as will enable othersskilled in the art to which it appertains to make and use the same.

This invention relates to foam stabilizers particularly adapted for usein solutions which, when mixed, are capable of forming foam blankets forthe purpose of extinguishing fires. The invention more particularlyrelates to foam stabilizers produced from relatively inexpensive wastematerials.

It is to be understood that the use of foam blankets forfire-extinguishing purposes has been practiced for many years. Toproduce these blankets solutions capable of releasing a gas such ascarbon dioxide and containing the stabilizer are mixed at or adjacent tothe fire and the mass of bubbles produced by the reaction is applied tothe fire to shut off the supply of oxygen therefrom. The function of thestabilizer is to increase the toughness and tenacity of the foam so thatit will effectively accomplish the desired result. The solutions usedcontain generally sodium bicarbonate and aluminum sulphate respectively,the foam stabilizer being mixed usually with the sodium bicarbonatesolution.

The stabilizer heretofore commonly used in fire-extinguishing solutionsfor the purpose of producing foam blankets is an extract of licoriceroot which gives to the foam'the desired toughness and tenacity andinsures the successful accomplishment of its intended purpose. Manysuggestions have been made heretofore regarding the substitution ofother foam stabilizers such as black liquor from the manufacture ofpaper pulp, glue, saponin, etc., for the extraction of licorice root.proved to be effective or are less satisfactory than extract of licoriceroot which has been employed almost exclusively as a foam stabilizer infire-extinguishing compositions. It is the object of the presentinvention to pro vide a foam stabilizer which is relatively inexpensiveand is equal to or more eflective than the extract of licorice rootheretofore The substitutes have not Application filed December 18, 1923.Serial No. 681,429.

Other objects and advantages of the invention will be apparent as it isbetter understood by reference to the following specification.

My research has disclosed a source of material suitable for use as afoam stabilizer having all of the desirable properties of materialheretofore suggested for that purpose and being derived preferably froma Waste product so that the cost thereof is reduced to a minimum. I havediscovered that certain barks when suitably extracted provide a verysatisfactory foam stabilizer and that the stabilizer may be usedadvantageously in connection with fire-extinguishing solutions for thepurpose of providing a tough and tenacious foam blanket.

Although the product may be prepared from the barks in their originalcondition, they are preferably first extracted for the production ofother products. In fact, the

arks which I employ are extracted for the purposeof producing commercialproducts such as dye-stuffs and tanning extracts. The residual materialis considered as waste,

and previous to my invention was utilizedas a low grade fuel. This wastematerial is, however, subjected to a secondary extraction under suitableconditions to separate a foam stabilizer therefrom and the extract isutilized for the purpose of the invention.

In carrying out the invention I employ preferably quercitron or blackoak bark (Querous oelutina of Lamarck, also known as Quercus tinctom'aof Bartram and as Quercus coccz'nea var. zz'notom'a of De Candolle).This bark produces upon primary extraction with water and steam underpressure, a valuable yellow dye-stuff which, however, has no utility asa foam stabilizer. When the extracted bark is subjected to a secondaryextraction the foam stabilizer is ob- I tained. The secondary extractionis preferably conducted with an alkaline solution such as caustic soda.About 8% of caustic soda figured on the weight of the dry material isemployed The extraction is carried out under a steam pressure ofapproximately 45 pounds which is maintained until the extraction issufiiciently completed, that is to say, when the specific gravity of theliquor is about 1.045 or equivalent to 9 Twaddle. Two or more hours maybe required for the extraction. After the liquor is blown oif from theextractor it is filtered such as are used in fire-extinguishingcornposltlons. These solutions when used with the extract show verylittle if any sediment after long standing, theproduct being markedlysuperior in this respect to foam stabilizers now to be found in themarket.

In employing the extract for fire-extinguishing purposes two solutionsare employed. The proportions as hereinafter specified are suggestivemerely as the compositions may be varied considerably.

Solution N0. 1.

Per cent. Bicarbonate of soda Extract of black oak bark 3 Water 88Solution No. :2.

Per cent. Aluminum sulphate 13 a Water 87 These solutions are maintainedin separate COIltillIlGIS. until the need for the fireextlngulshingblanket occurs. The solutions arethen mixed and the chemical reactionresults in the production of a large volume of carbon dioxide. Thelatter is released in the solution and produces a mass of bubbles which,owing to the presence of the foam stabilizer, are extremely tough andtenacious. When this foam is applied to a fire, oxygen from theatmosphere is substantially prevented from reaching the combustiblematerial and the fire is consequently extinguished promptly.

An equally valuable foam stabilizer may be produced from a similarmaterial. chestnut oak bark including the species Querous muhlenbergiiof Engelmann, Q-ucrcus prz'nus of Linnaeus and Q'r'lercus michaumii ofNut-" tall. This material is ordinarily extracted to obtain a tanningextract and the spent bark heretofore has been utilized merely as afuel. When subjected to a secondary extraction in the mannerhereinbefore described I obtain a solution which is substantially likethat obtained from the secondary extraction of. black oak bark, that isto say, a solution which may be used advantageously as a foam stabilizerin fireextinguishing com ositions such as that de-' scribed herein. T eextracts from both of these barks have substantially the same propertyand may be utilized interchangetain extent with the valuable materialswhich arcordinarily extracted with water, and to that extent the yieldof foam stabilizer would be somewhat less and its efli ciency would bereduced. It is preferable, accordingly, first to subject the bark towater extraction as described and to produce a foam stabilizer by asecondary extraction. This practice will usually be followed since theextraction of dye-stuffs and tannin from the barks mentioned is anestablished industry and large quantities of bark which have beensubjected to the primary extraction are available and can be obtained ata relatively low' cost. The supply of such extracted bark is such thatthe bark is an economical and desirable source of foam stabilizers.

The foam stabilizer prepared as hereinbefore described may be utilizedadvantageously in liquid form in which it may be added to one or theother of the water solutions of the fire-extinguishing com osition. Itis also desirable to use the 0am stabilizer in a-solid form in which itmay be added to the dry ingredients of the fireextinguishingcomposition. For this purpose the liquid stabilizer may be crystallizedby subjecting it to evaporation in a vacuum pan, for example, andreducing the moisture content until the solids crystallize therefrom.This provides a crystalline or granular material which may be mixed, forexample, with the bicarbonate of soda. I The mixture may be packaged indry form and in quantity sufiicient to furnish a standard ized chargefor a fire-extinguisher. Aluminum sulphate may be packaged likewisev andconsequently the solutions may be prepared by merely adding the requiredamount of water to the contents of the packages.

While the extract is described more espc cially as a stabilizer forfire-extinguishing foam, it may be utilized advantageously for otherpurposes. I intend, therefore. to claim the product for all purposes towhich it is adapted.

-Various changes may be made in the details of the method of extractionas herein! before described without departing from the invention orsacrificing any of the advantages set forth.

I claim 1. A foam stabilizer consisting of an extract of black oak bark.

2. A foam stabilizer consisting of a sec ondary extract of black oakbark;-

III

an alkaline solution after 3. foam stabilizer consisting of an extractof oak bark.

4. A foam stabilizer consisting of a secondary extract of oak bark.

5. A foam stabilizer for fire-extinguishing compositions and similarurposes consisting of the extract obtaine by subjecting black oak barkto the action of. an alkaline solution. y

6. A foam stabilizer for fire-extinguishing compositions and similarpurposes con-' sisting of a secondary extract obtained by subjectingblack oak bark to the action of a primary extraction with water.

7. A foam stabilizer for fire-extinguishing compositions and similarpurposes consisting of the extract obtained by subjecting oak bark tothe action of an alkaline solu- 39 tion.

8. A foam stabilizer for fire-extinguishing compositions and similarpurposes consisting of the extract obtained by subjecting spent oak barkfrom which the watersoluble constituents have been separated to the.action of an alkaline solution.

9. A foam stabilizer consisting of a crystalline extract of oak bark.

10. A foam stabilizer consisting of a dry granular extract of oak bark.

11. A composition for use in extinguishing fires comprising a drygranular extract of black oak bark combined with a gasreleasing agent.

12. A composition for use in extinguishing fires comprising extract ofoak bark in a dry granular condition combined with a gas-releasingagent.

In testimony whereof I afiix my signature.

NATHANIEL T. EWER.

